Unless you are a recruited athlete sports don’t count as more than any other EC activity. I’d say to do what you like to do.
I would look to see if you can find ways to get recognized in one of the activities you are involved in (perhaps place in a competition) or get involved with a formal group for one or more of your sports (perhaps there are mountain biking, surfboarding organizations etc. to join in your community) as a way to validate that you are involved in those activities in a meaningful way. Keep in mind that EC activities do not have to be in the school, they can be anything you do in the community, with your sports etc.
For now you should focus on:
–Working hard, learning, and doing as well as you can in the most challenging curriculum you can manage.
–When the time comes study for standardized tests.
–Continue your involvement in activities you care about and work towards making meaningful contributions to those activities.
–Enjoying spending time with your family and friends.